I have been consulting for about 8 years now. Sending clients a w9 has been standard. I just expanded my consulting business to include selling a computer modeling program. I just made my first sale and the customer is requesting a w9 so they can send out a 1099 at the end of the year. I'm confused because I assumed when you sell a product rather than a service, you aren't receiving income. I mean, I didn't ask HP for a w9 and send them a 1099 after buying my laptop. Of course I will report my profits on sales as income on my tax return, but I guess I am looking for confirmation that my software customers don't need a w9 from me.